You won't be able to level the Jeep with the large snow blade on the front. It will take some work when you install the blade and run that during the winter, but then once the blade is removed, the front will go up due to the weight loss. The blade's weight is also so far ahead of the axle/spring that it acts as a twisting weight as well, pulling like a torque arm. This also reacts to the rear axle by lifting the rear pivoting off the front axle.
V8 Grand Cherokee springs should probably have the stiffest spring rate stock from Jeep. However, the unloaded height may not be equal or close to equal to use in the TJ stock coil. Spring rate is the amount of weight the spring will carry per inch compression. If the spring was 100#/in, then it would compress 1" for the 100#s, 2" for 200#s, etc.
When you add the blade to the front of your Jeep, measure the before and after install height of the coil. You may only need to add another coil spacer on top of the coil.
I run Rubi Unlmtd coils on my 4cyl TJ and they gave me less than 1" lift overall. This is due to the spring rate difference between tired old 97 coils vs 05 Rubi coils. I've added ACOS to the front to help level the TJ as well. With a 2" poly spacer in the back, then adding winch up front with bumpers, etc. I used the ACOS to adjust the front height and level the TJ.
